Re: [PATCH v3 11/23] iommufd/viommu: Add IOMMUFD_CMD_VQUEUE_ALLOC ioctl

Vasant Hegde
2025-05-08T04:49:49Z

Jason,

On 5/7/2025 6:01 PM, Jason Gunthorpe wrote:
> On Wed, May 07, 2025 at 01:11:43PM +0530, Vasant Hegde wrote:
>> - MMIO Offset 0018h IOMMU Control Register
>> EventLogEn: Event log enable
>> * When guest sets this bit, qemu will trap and will send queue_alloc
>> * When guest disables this bit, qemu will trap and send vqueue_destroy
>>
>> This part is fine.
>
> Ok
>
>> EventIntEn: Event log interrupt enable
>> * When guest sets this bit, qemu will trap
>> * this needs to be communicated to Host so that we can program VF Control
>> BAR and enable the interrupt
>
> This sounds like modifying the vqueue? Or maybe on the viommu?

IMO its VIOMMU as it informs HW to trigger interrupt or not.

>
>> - There is other bit "Completion wait interrupt enable"
>> This doesn't related to any buffer. Instead if we configure this for
>> completion wait command it will generate interrupt.
>
> This sounds like a modify on the VIOMMU object?

Again in my view its VIOMMU object as it tells HW what to do when it finishes
completion wait command.

-Vasant